A bottom-feed electrically operated fuel injector is typically characterized by the fact that its fuel inlet is disposed proximal to its fuel outlet and distal to its electrical connector. For example, the fuel inlet may be disposed in the sidewall of the injector body while the fuel outlet is disposed at one axial end of the body and the electrical connector is disposed at the opposite axial end of the body. The typical mounting of such a fuel injector on a fuel rail comprises the fuel injector being disposed in a transverse through-hole in the rail such that: the injector's fuel inlet is in fluid communication with a main longitudinal fuel passage in the fuel rail; the fuel injector's body is sealed to the wall of the transverse through-hole on axially opposite sides of the injector's fuel inlet; the injector's electrical connector is disposed at one axial end of the transverse through-hole so as to be available for connection to a mating electrical connector that delivers operating current to the injector; and the injector's outlet is disposed at the opposite axial end of the through-hole for injecting fuel into the engine for entrainment with combustion air.
It is a typical practice to mount a bottom-feed fuel injector on a fuel rail by inserting the fuel injector, outlet end first, into the transverse through-hole in the fuel rail until the insertion is arrested by abutment with an abutment stop located a predetermined distance inside the through-hole. A cover, which may include an electrical connector for connecting to the electrical connector of the fuel injector, is then disposed over the proximal end of the injector and fastened to the fuel rail to capture the installed injector in the through-hole. Examples of known practices are evidenced by U.S. Pat. Nos. 4,475,486; and 4,844,036. An example of a clip attachment for a top-feed injector is shown by U.S. Pat. No. 4,475,516.
Circumferential orientation of a fuel injector within a transverse through-hole in a fuel rail may also be important. Such is usually the case where the injector is of the split-stream type. It is therefore desirable to provide a circumferential locator for assuring the proper circumferential orientation of a fuel injector in a transverse through-hole in a fuel rail. Examples are evidenced by certain commonly assigned co-pending applications that are known to the USPTO by virtue of their pendency.
The present invention relates to a novel mounting of an electrically operated fuel injector on a fuel rail which may be especially useful for certain engine applications. The invention comprises the inclusion of a keying means associated with one of the through-hole and the injector and a keyed means associated with the other of the through-hole and the injector. The keying means and keyed means are effective to permit the one to pass axially through the other during insertion of the fuel injector into the through-hole, provided that the fuel injector is properly circumferentially oriented to register the keyed means with the keying means, and to permit the fuel injector to be twisted about its own axis after having been fully inserted into the through-hole such that the keying means and the keyed means are removed from registry and are instead placed in an interference relationship preventing the fuel injector from being extracted from the through-hole. An abutment stop is also provided on the one of the keying means and keyed means that is associated with the through-hole for abutment with the fuel injector for the purpose of limiting the extent to which the fuel injector can be twisted once the fuel injector has been fully inserted into the through-hole, thus enabling the fuel injector to be properly circumferentially oriented within the through-hole. The disclosed embodiment of the invention comprises a pair of bayonet lugs on the injector body which constitute the keyed means and an annular disc which is mounted on the fuel rail in the through-hole and embodies a pair of bayonet slots which constitute the keying means.
Further details of the invention, along with advantages and benefits of the invention, will be seen in the ensuing description which is accompanied by drawings. The drawings disclose a preferred embodiment of the invention according to the best mode contemplated at the present time for carrying out the invention.